[tip: sched/urgent] x86/itmt: Don't make ITMT enablement depend on debugfs

[tip-bot2 for Mario Limonciello]

The following commit has been merged into the sched/urgent branch of tip:

Commit-ID:     eaece4849991d62fcd6f46637c55dcce00e25d70
Gitweb:        https://git.kernel.org/tip/eaece4849991d62fcd6f46637c55dcce00e25d70
Author:        Mario Limonciello <mario.limonciello@xxxxxxx>
AuthorDate:    Mon, 31 Aug 2026 00:38:33 -05:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Wed, 02 Sep 2026 09:17:50 +02:00

x86/itmt: Don't make ITMT enablement depend on debugfs

sched_set_itmt_support() treats debugfs file creation failures as fatal.
When CONFIG_DEBUG_FS is disabled, debugfs stubs return ERR_PTR(-ENODEV),
causing ITMT to be silently disabled.

debugfs is a debug-only facility; its return values should be ignored.
Drop the fatal error handling and enable ITMT unconditionally.

Fixes: d04013a4b21b ("x86/itmt: Move the "sched_itmt_enabled" sysctl to debugfs")
Reported-by: Klaus Kusche <klaus.kusche@xxxxxxxxxxxxxxx>
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Reviewed-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>
Tested-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>
Link: https://patch.msgid.link/20260831053836.1881864-1-mario.limonciello@xxxxxxx
---
 arch/x86/kernel/itmt.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/itmt.c b/arch/x86/kernel/itmt.c
index 243a769..85ebde3 100644
--- a/arch/x86/kernel/itmt.c
+++ b/arch/x86/kernel/itmt.c
@@ -110,18 +110,14 @@ int sched_set_itmt_support(void)
 						    arch_debugfs_dir,
 						    &sysctl_sched_itmt_enabled,
 						    &dfs_sched_itmt_fops);
-	if (IS_ERR_OR_NULL(dfs_sched_itmt)) {
+	if (IS_ERR(dfs_sched_itmt))
 		dfs_sched_itmt = NULL;
-		return -ENOMEM;
-	}
 
 	dfs_sched_core_prio = debugfs_create_file("sched_core_priority", 0644,
 						  arch_debugfs_dir, NULL,
 						  &sched_core_priority_fops);
-	if (IS_ERR_OR_NULL(dfs_sched_core_prio)) {
+	if (IS_ERR(dfs_sched_core_prio))
 		dfs_sched_core_prio = NULL;
-		return -ENOMEM;
-	}
 
 	sched_itmt_capable = true;